Throughout this application, various references are referred to within parenthesis. Disclosures of these publication in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains. Full bibliographic citation for these references may be found at the end of each series of experiments in the Experimental Details section.
Wilson's disease (WD) is an autosomal recessive disorder of copper metabolism with a world-wide prevalence of 30 per million and a corresponding carrier frequency of 1 in 90. Biochemically it is characterized by abnormally high concentrations of copper in a number of organs and tissues, and deficiency of the plasma copper-protein, ceruloplasmin. The excess copper causes damage to the liver and brain. In the former, acute and chronic hepatic disease progresses to cirrhosis; in the latter motor and psychiatric disturbances reflect the cerebral pathology. Clinical onset may occur in the latter half of the first decade, is most frequent in adolescence, and was delayed in two patients until the seventh decade. Untreated, the disease is always fatal but pharmacologic removal or detoxification of the excess copper is prophylactic in the asymptomatic patient and can be dramatically effective therapy for patients with hepatic or cerebral symptomatology. The mechanism by which the abnormal gene disturbs copper homeostasis is unknown (1).
In 1985, genetic linkage studies showed that the Wilson's disease locus segregates with the red cell enzyme esterase-D (ESD) on chromosome 13 (2). Subsequent linkage analyses limited the disease locus to a genomic region bracketed by the DNA marker loci D13S31 and D13S59, although the odds for a disease locus in the adjacent interval between loci D13S31 and D13S25 were estimated to be only seven times less likely (3).